A device for predicting an exhaust gas recirculation rate of an internal combustion engine, which comprises an inlet system and at least one exhaust gas recirculation valve, is described. The device comprises a sensor arranged in the inlet system for determining the composition of the gas, a sensor for determining the position of the exhaust gas recirculation valve, and an evaluation apparatus. The evaluation apparatus is configured to determine and output a prediction of the exhaust gas recirculation rate based on a corrected estimate of the exhaust gas recirculation rate, wherein the estimate is based on the position of the exhaust gas recirculation valve and is corrected based on the composition of the gas as determined using the sensor.

An internal combustion engine 2 is started by being cranked by an electric motor. An internal combustion engine start control device performs a feedback-control of an intake air amount of the internal combustion engine to a target idle intake air amount, learns a feedback correction amount applied in a feedback control, and performs a learning control using a learnt value in parallel with the feedback control. An engine rotation speed is converged to a target idle rotation speed in an early stage by setting an allowable correction range of a feedback correction amount applied before a start of learning of the intake air amount wider than the allowable correction range of the feedback correction amount applied after the start of the learning of the intake air amount.

An internal combustion engine 2 is started by being cranked by an electric motor. An internal combustion engine start control device performs a feedback-control of an intake air amount of the internal combustion engine to a target idle intake air amount, learns a feedback correction amount applied in a feedback control, and performs a learning control using a learnt value in parallel with the feedback control. An engine rotation speed is converged to a target idle rotation speed in an early stage by setting an allowable correction range of a feedback correction amount applied before a start of learning of the intake air amount wider than the allowable correction range of the feedback correction amount applied after the start of the learning of the intake air amount.

Based on entry/exit pressures of a compressor detected by atmospheric/boost pressure sensors, a pressure ratio of compressor is calculated. Based on mass flow rate and entry temperature of intake air detected by intake air flow-rate/temperature sensors and entry pressure, a volumetric flow rate of intake air is calculated in environmental condition at a detection time using gas state equation, and is corrected into a volumetric flow rate under standard environmental condition thorough multiplication by a corrective coefficient based on entry temperature of intake air. Based on the corrected value and the calculated pressure ratio, a rotational frequency of compressor under standard environmental condition is read out in light of operating characteristic diagram for the compressor. Read-out rotational frequency is corrected into actual rotational frequency of the compressor through multiplication by a corrective coefficient based on entry temperature of intake air, which is determined as rotational frequency of turbocharger.

Based on entry/exit pressures of a compressor detected by atmospheric/boost pressure sensors, a pressure ratio of compressor is calculated. Based on mass flow rate and entry temperature of intake air detected by intake air flow-rate/temperature sensors and entry pressure, a volumetric flow rate of intake air is calculated in environmental condition at a detection time using gas state equation, and is corrected into a volumetric flow rate under standard environmental condition thorough multiplication by a corrective coefficient based on entry temperature of intake air. Based on the corrected value and the calculated pressure ratio, a rotational frequency of compressor under standard environmental condition is read out in light of operating characteristic diagram for the compressor. Read-out rotational frequency is corrected into actual rotational frequency of the compressor through multiplication by a corrective coefficient based on entry temperature of intake air, which is determined as rotational frequency of turbocharger.

An apparatus for controlling an EGR valve, includes: a measurement unit to measure at least one operation condition of an engine system; a fresh air amount setting unit to set a target amount of fresh air based on the operation condition; a fresh air amount sensor to measure a current amount of fresh air introduced through an intake line; a control calculation unit to set a signal for controlling an opening degree of the EGR valve so that the current amount of fresh air follows the target amount of fresh air; and an identifier to simulate an input and an output of the engine system, and output engine system input-output sensitivity which is a ratio of a change rate of the current amount of fresh air to a change rate of the opening degree of the EGR valve.

Examples of the present disclosure describe systems and methods for determining an estimated ambient air temperature in an environment in which a vehicle is operating. The estimated ambient air temperature may be compared to an ambient temperature sensor value. The comparison may be used to determine whether an ambient air temperature sensor of the vehicle is functioning properly or if an error notification or fault code should be triggered.

Methods and systems are described for diagnosing degradation of a vacuum actuator in an engine system. An example method comprises indicating degradation of the vacuum actuator based on an estimate of flow of air into and out of a vacuum reservoir. The estimate is further based on flow of air generated via each of an aspirator in the intake system, an actuation of the vacuum actuator, and leakage during the actuation of the vacuum actuator.

Methods and systems are described for diagnosing degradation of a vacuum actuator in an engine system. An example method comprises indicating degradation of the vacuum actuator based on an estimate of flow of air into and out of a vacuum reservoir. The estimate is further based on flow of air generated via each of an aspirator in the intake system, an actuation of the vacuum actuator, and leakage during the actuation of the vacuum actuator.

The invention relates to a method and to a device for adjusting a charging pressure in an internal combustion engine by means of a pressure-wave supercharger, wherein the pressure-wave supercharger has a cell rotor, which passes through at least two compression cycles per revolution, wherein a high-pressure exhaust-gas flow is divided into a first and a second high-pressure exhaust-gas partial flow, wherein a fresh-air flow and the first high-pressure exhaust-gas partial flow are fed to the cell rotor and a first compressed fresh-air flow and a low-pressure exhaust-gas flow are led away from the cell rotor in the first compression cycle, and wherein the fresh-air flow and the second high-pressure exhaust-gas partial flow are fed to the cell rotor and a second compressed fresh-air flow and the low-pressure exhaust-gas flow are led away from the cell rotor in the second compression cycle, wherein the first and the second compressed fresh-air flow are combined into a charge air, and wherein the charge air is fed to the internal combustion engine, wherein the second high-pressure exhaust-gas partial flow is controlled in order to control the charging pressure of the charge air in such a way, and wherein the second compressed fresh-air flow is led through a check valve before the first and the second compressed fresh-air flow are combined into the charge air.